Abstract Aeromonas schubertii is a conditional pathogen widely distributed in aquatic environments, yet it was only recently reported as a causative pathogen in fish. This study investigated antioxidant capacity, non-specific immunity, histopathology and immune-related gene expression profiles in Nile tilapia Oreochromis niloticus injected with A. schubertii. The results show that A. schubertii infection stimulated the activation of antioxidant activity and non-specific immunity in Nile tilapia. Histopathological analysis revealed that inflammation existed in the liver, spleen, head kidney, brain and intestine of the infected fish. Quantitative real-time PCR was performed to measure mRNA expression levels of six immune-related genes (interleukin-1β, tumor necrosis factor-α, cyclooxygenase-2, transforming growth factor beta, interleukin-10 and heat shock protein 70) in the intestine and head kidney at different timepoints after experimental infection. The results demonstrated clear transcriptional activation of these immune-related genes in the intestine and head-kidney tissues. To our knowledge, this is the first study to investigate the host response to A. schubertii infection in a fish. These results will contribute to further understanding of the pathogenesis and host defense system in fishes following infection with A. schubertii.

中文翻译：

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感染舒伯特气单胞菌的尼罗罗非鱼 Oreochromis niloticus 的抗氧化能力、非特异性免疫、组织病理学分析和免疫相关基因表达

摘要 舒伯特气单胞菌是一种广泛分布于水生环境的条件性病原体，但最近才报道它是鱼类的致病病原体。本研究调查了注射 A. schubertii 的尼罗罗非鱼 Oreochromis niloticus 的抗氧化能力、非特异性免疫、组织病理学和免疫相关基因表达谱。结果表明，A. schubertii 感染刺激了尼罗罗非鱼的抗氧化活性和非特异性免疫的激活。组织病理学分析显示，感染鱼的肝脏、脾脏、头肾、脑和肠道存在炎症。进行定量实时 PCR 以测量六种免疫相关基因（白细胞介素-1β、肿瘤坏死因子-α、环氧合酶-2、转化生长因子β、实验感染后不同时间点肠道和头肾中的白细胞介素 10 和热休克蛋白 70）。结果表明这些免疫相关基因在肠和头肾组织中的明显转录激活。据我们所知，这是第一项研究宿主对鱼中舒伯特曲霉菌感染的反应的研究。这些结果将有助于进一步了解鱼类感染舒伯特氏菌后的发病机制和宿主防御系统。鱼中的舒伯特氏菌感染。这些结果将有助于进一步了解鱼类感染舒伯特氏菌后的发病机制和宿主防御系统。鱼中的舒伯特氏菌感染。这些结果将有助于进一步了解鱼类感染舒伯特氏菌后的发病机制和宿主防御系统。